Therapeutic recombinant proteins: trends in US approvals 1982 to 2002

Recombinant proteins have become an important class of therapeutics since the first product was approved for marketing in the US in 1982. To determine trends in the clinical development and approval processes for therapeutic recombinant proteins, data for 270 products that entered clinical study in the period 1980 to 2002 were collected and analyzed. Mean clinical and approval phase lengths for 54 US-approved products stratified by time period, therapeutic indication, protein type, review rating and FDA review center are compared. Approval success rates, calculated using three methods that differ only in the definition of success, and the variation of approval success rates over five time periods are presented.